Broad Objective: To evaluate adult Maryland Medicaid patients' patterns of use of hospital emergency departments (EDs) for the treatment of mouth pain and infections associated with teeth and periodontal tissues. Additionally, changes in the frequency of ED dental visits resulting from the elimination of adult Medicaid reimbursement to dentists for the treatment of dental emergencies will be examined. Rationale: Pain from toothaches represents a significant public health problem. The poor and minorities who lack access to private dental services may utilize EDs for the treatment of these and related conditions. EDs generally lack dental services, and thus, are usually not capable of providing definitive treatment for oral conditions. Specific Aims: 1 - To determine the rate with which Medicaid patients visited hospital emergency departments (EDs) for the treatment of mouth pain and infections associated with the teeth and periodontal tissues in Maryland from February 1990 to February 1996; 2. To determine whether the rate of visits changed after the institution of a policy (in February of 1993) to eliminate Medicaid reimbursement for emergency visits to dentists' offices; 3. To determine projections of the cost savings from reduced dental office visits and any resulting cost shifting from increased ED visits for the periods before and after the policy revision. Research Design: This study examines the use of EDs, during the six-year period February 16, 1990 to February 15, 1996, for the treatment of mouth pain and infections associated with the teeth and periodontal tissues. The study employs an observational quasi- experimental design with two study groups defined as follows: adult Medicaid patients using the ED for dental problems prior to February 16, 1993 and adult Medicaid patients using the ED for dental problems after February 15, 1993. The study employs a natural experiment, the change in Medicaid policy which eliminated dentist reimbursement, to establish the two study periods. Data tapes describing Medicaid patients use of EDs will be obtained from the Medicaid Management Information System which is maintained by the Maryland Department of Health and Mental Hygiene. This system includes a claims database from which dental related visits can be identified (based on ICD-9-CM Codes) and costs can be quantified. It also includes recipient files from which the total number of person-years of coverage can be quantified. Using these sources of information, it will be possible to calculate the number and cost of dental related ED visits per person-year of Medicaid eligibility both before February 16, 1993 and after February 15, 1993. Descriptive and inferential statistical methods will be used to analyze the data.